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CSS Flexbox Playground

Experiment with flex-direction, wrap, justify-content, align-items and gap — live preview and copyable CSS.

Related tools

All Colours & CSS tools →
CSS CompressorMinify CSS by stripping comments and whitespace to shrink your stylesheet's size.CSS Grid GeneratorBuild a CSS grid layout visually — columns, rows, gaps and alignment — with a live preview and copyable CSS.CSS BeautifierReformat minified or messy CSS into clean, properly indented rules — or minify it back.CSS Box Shadow GeneratorDial in a CSS box-shadow with live preview and copy the generated code — offset, blur, spread, color, inset.Color Contrast CheckerWCAG contrast ratio between text and background, with AA/AAA pass-fail and a live preview.Color InverterInvert a colour (255 − RGB) or take its complement, in HEX/RGB/HSL/CMYK with the contrast between them.Color Scheme GeneratorDerive complementary, analogous, triadic, tetradic, split and monochromatic schemes from a base colour.Gradient GeneratorBuild a linear or radial CSS gradient from two colours and an angle, with CSS and Tailwind output.

Open CSS Flexbox Playground and you get an answer straight away, with no account to create. Its place is under Colours & CSS; CSS Compressor and CSS Grid Generator answer the questions closest to this one.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is CSS Flexbox Playground?

Experiment with flex-direction, wrap, justify-content, align-items and gap — live preview and copyable CSS.

When would I actually use this?

Moving a colour between a design tool and a stylesheet, building a palette around one brand colour, and checking text will be readable on it.

What is the most common mistake?

Judging contrast by eye. Two colours that look distinct on a bright monitor can fail the accessibility ratio outright, and the ratio is the thing an audit will measure.

How is CSS Flexbox Playground different from CSS Compressor?

They sit next to each other but answer different questions: CSS Compressor is the one to open when you need it to minify CSS by stripping comments and whitespace to shrink your stylesheet's size. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

CSS Grid Generator is the closest one after this: Build a CSS grid layout visually — columns, rows, gaps and alignment — with a live preview and copyable CSS.

What else is worth having open alongside it?

CSS Beautifier and CSS Box Shadow Generator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Conversions between HEX, RGB and HSL are exact. Contrast follows the WCAG 2 relative-luminance formula; CMYK is device-dependent, so a screen value is an approximation of what will print.

Further reading

All guides →
ExplainerGradients, Banding, and Why the Middle Looks MuddyInterpolating in sRGB averages gamma-encoded numbers, so the midpoint of red to green is #808000 when the half-light answer is #bcbc00 — 57.2% too little light. Banding is a separate arithmetic problem: 8 bits give 256 steps, and a dark gradient may have only 28 of them. Here is both, computed.ExplainerColour Schemes Are Geometry on a Wheel — and the Wheel Is WrongComplementary, triadic, analogous and split-complementary are just rotations: add 180°, 120°, 30° or 150° to a hue. The arithmetic is trivial. The problem is that the HSL hue circle is not perceptually uniform — yellow and blue at the same HSL lightness differ in luminance by 12.85 times — so a generated palette has to be contrast-checked afterwards.GuideWhat a Minifier Can Remove, and What It Must NotMinification has to preserve meaning, and the interesting part is the whitespace that carries meaning: the descendant combinator, the spaces inside calc(), the gap between two inline elements. Measured here on real files, including how much brotli was going to save you anyway.ExplainerContrast Ratio: How WCAG Actually Computes ItThe WCAG ratio is (L1 + 0.05) ÷ (L2 + 0.05), and L is relative luminance, not brightness. Green carries 71.52% of it and blue 7.22%, which is why pure blue on white passes at 8.59:1 while mid grey fails at 3.95:1. Here is the whole computation, run end to end.How-toHEX vs RGB: How to Read and Convert ColoursHEX and RGB are two notations for the same colours. Here's how to read each, convert between them, and add transparency.GuideBeautify or Minify: What Each Is For, and What It Does to the WeightFour real stylesheets run through the minifier, measured raw and after gzip. Stripping every space saved 48, 103, 104 and 147 compressed bytes; stripping comments saved 57, 1 358, 2 420 and 1 042. Plus the five inputs this minifier breaks.